A method of determining identifiers for tagging frames of animation with is provided. The method comprises obtaining data indicating motion of an animated object in a plurality of frames and detecting the object as performing a pre-determined motion in at least some of the plurality of frames. For a given frame, it is determined based on the detected pre-determined motion, whether to associate an identifier with the pre-determined motion, the identifier indicating an event that is to be triggered in response to the pre-determined motion. The frames of the animation comprising the detected pre-determined motion are tagged, in response to a determination of an identifier. The pre-determined motion and corresponding identifier are determined by inputting the obtained data to machine learning model. A corresponding system is also provided.